Everyone knows that Microsoft Exchange is expensive - but ubiquitous â€" and plenty
of open source projects and vendors have been trying a variety of technical
approaches to replace it. While none is yet a drop-in replacement, a PC World article looks at ways that some administrators can get a cost advantage by switching.

Likewise is *not* a replacement, it actually brings your non-Windows systems *into* Active Directory. The free version is very limited, it is not much more than an automation for samba+keberos+pam+nsswitch setup tasks, which is nice.. until it breaks..

If I decide to join a Linux box to AD, I usually just do it manually.. or if the customer insists, I set it up using NIS/NIS+ & AD.

Just to clarify something mentioned in the parent.. Likewise is *not* a replacement, it actually brings your non-Windows systems *into* Active Directory. The free version is very limited, it is not much more than an automation for samba+keberos+pam+nsswitch setup tasks, which is nice.. until it breaks.. If I decide to join a Linux box to AD, I usually just do it manually.. or if the customer insists, I set it up using NIS/NIS+ & AD.

Just to clarify your clarification ... wouldn't it be possible to use Samba 4 as the replacement for Active Directory, and in addition use Likewise to manage it?